It is a per-account aggregate of measures about average CPU usage, memory usage,
peak loads, and other factors related to real-time operations.
Rootroute whatches its servers do not approach overload limits,
and that each account gets the computing resources they asked.

What it is used for ?

It is used to limit the number of account per server.
Also, it is used to give a fair share of system resources to each account.
Some ISP says things like "we put at most 50 users per server",
however that does not mean anything since a few users can easily
chew up all resources.

Can you detail on this SARI ?

The rootr.net method balances and distribute user resources.
Also if a user "eats" too much resources, his/her account may be moved
to a separate server, transparently.

Additionally, servers come in different capacity. Certain types of
expensive servers are capable of handling over a 1000 users
without noticing any difference in performance.
Other servers may start getting breathless with only 20 users.
This is dependant on 4 factors:

Hardware equipement and hardware configuration.

Software such as operating system kernel configuration.

The engineering art of whoever sets up and maintains the server.

The time he/she has available. Good work does take time.

These factors affects cost, performance, and stability.
Each server has a different total SARI. The server average,
of all operational servers with rootr.net, is 100.

Therefore when rootr.net total capacity increases,
Your account with rootr.net also increases, yet retains the same pricing.

What if I go over my SARI index ?

This does not happen very often, as hosting plans are made according user
resource usage, with a fair margin for the occasional overhead.
However if your account goes over, you will be notified, with an
option to upgrade or add resource allocation for a minimal charge.

If only a few processes endanger the stability of server operation,
the processes can be ended automatically or manually by a system
administrator.